Transistor Led Flasher

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This circuit has only two transistors, two capacitors and four resistors. That also means it consumes very little power

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You can control the flash rate by changing the size of the 47k resistors. You can also control the duty cycle by using resistors of different values on the two sides. The 330 ohm resistors control the current through the LEDs. Normally you want to limit this to 20mA, but to conserve battery power, you may need to limit it even further. You can also connect several LEDs in series, instead of using only one for each side. With red LEDs (1 per side) and the values shown, the circuit draws about 11mA. 

Part List

c828         = 2

330 Ohm  = 2

47k           = 2

47uF         = 2 

LED          =2